The Search for Spock is THE gold standard and it was the first thing I thought of before I read the second half of Zack's tweet.

I can think of a lot of GOOD ones, but few on that level. The Revenge of the Sith one was surprisingly good in how it handled Anakin's turn https://twitter.com/MuseZack/status/1310774124898205696

older novelizations were written under fewer restrictions and the writers had more of a free hand to expand on the screenplay. Now that's done less frequently AND when they can, the publishers clamp down on even including deleted scenes if they can be caught in time

B.B. Hiller's novelization of SUPERMAN IV: THE QUEST FOR PEACE was much improved over the film. Blew my mind the first time I read it and learned there was an entire other Nuclear Man AND a near-miss on WWIII. For years I was convinced those deleted scenes would have saved it

Alas... WB eventually included those Deleted Scenes on the bluray and they look like the work of a crazy person. Goes to show you how bad directing can really bone something that seems like it should work on the page